This multicenter, prospective, partially-blinded primary prevention trial seeks to identify therapy that will significantly reduce sudden death rates in patients with congestive heart failure resulting from ischemic cardiomyopathy or nonischemic dilated cardiomyopathy. All patients will receive standard heart failure treatment, but will also be randomized to three arms: standard treatment plus placebo; standard treatment plus amiodarone; and standard treatment plus an internal cardioverter defibrillator. Patients will be followed through the end of 2001.